Comment by int_19h
Phonemic spelling does not require a syllabary, though. Several European languages are also written "as spoken" using the Latin alphabet, usually with a few extra digraphs or letter variants. Or you can make the syllabary itself compose regularly, like in Hangul.
Indian languages are generally rich in phonemes though. My mind boggles at the notion of [n] [ɳ] [ɲ] [ŋ] all being distinct. I mean, I can reproduce each one of them on its own, but doing that in rapid speech, and worse yet, recognizing the same in others' speech...
> My mind boggles at the notion of [n] [ɳ] [ɲ] [ŋ] all being distinct.
They are phonetically distinct, but not phonemically distinct, which is to say that in most places they occur, they aren't used to distinguish words or meanings.
In particular, the velar nasal "ङ" or "ng" always appears adjacent to a velar sounds (k/kh/g/gh) and similarly the palatal nasal "ञ" always appears adjacent to palatal sounds (c/ch/j/jh), both as allophones of the nasal phonemes "m" (bilabial) and "n" (alveo-dental), basically just like we speak in English under the exact same conditions (like the nasal in the word "English"!)
You perceive a difference with Indic language and English because the Latin script doesn't distinguish nasals for velar and palatal points of articulation - it only distinguishes by bilabial (m) and alveolar (n), whereas Indic scripts do distinguish those.
The unique nasal sound which is often contrastive in many Indian languages is the retroflex nasal "ण" (ṇ). That's the one that it's easy to confuse in speech if you are not a native speaker, so it's the only one you need to pay extra attention to when learning.